[ovs-discuss] Residual IP/ARP entry after a VM is powered off -> OVS passing unwanted pkts

Luiz Henrique Ozaki luiz.ozaki at gmail.com
Thu Sep 2 15:19:05 UTC 2010

Yes, thats what is happening.

Sorry for the long mail... I just figure what should be at the end of the

Unwanted packets received by the VMs seems not a good idea...

On Wed, Sep 1, 2010 at 2:59 PM, Ben Pfaff <blp at nicira.com> wrote:

> I only read your original message quickly, but if I understand it
> properly, it sounds to me like OVS is behaving in more or less the same
> way as a Ethernet switch would ordinarily behave.  If I understand your
> setup, initially you have a VM with a particular MAC address on some
> host.  Then you shut down that VM, so there is now nothing on the
> network with the MAC address in question.  OVS quickly sees that it
> hasn't had any packets from that MAC address on any port, so it starts
> flooding packets that are directed to that MAC to all ports.  It will
> continue to do that until the VM reappears.  (But eventually the hosts
> or VMs sending packets to that MAC will realize that they haven't had
> any responses in a while, time out that MAC, and fall back to ARPing for
> it, which effectively rate-limits the traffic.)
> Does that sound reasonable?

Luiz Henrique Ozaki
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